Musculoskeletal ultrasound using superb microvascular imaging documents treatment response to biosimilar infliximab in rheumatoid arthritis.

A 60-year-old woman with rheumatoid arthritis consulted for acute flare. She had elevated disease activity score 28 - erythrocyte sedimentation rate (DAS 28-ESR) of 6.88 and clinical disease activity index (CDAI) of 32. Her 12-joint ultrasound revealed widespread joint effusion. Synovial vascularity scores measured through superb microvascular imaging (SMI) and power Doppler were universally increased. We documented her treatment response 2 weeks after she received a single dose of biosimilar infliximab using clinical and sonographic data. Her DAS 28-ESR and CDAI scores decreased to 4.21 and 7.0, respectively. Reduction in synovial vascularity scores was demonstrated using SMI. While there was near total resolution in joint effusion and tenosynovitis, SMI was able to demonstrate synovial vascularity in joints with no clinical swelling nor tenderness. Musculoskeletal ultrasound and superb microvascular imaging are useful adjuncts in evaluating synovitis in rheumatoid arthritis and documenting treatment response through documentation of synovial vascularity, effusion and tenosynovitis.